There are literally thousands of different credit cards available. Some provide frequent flier miles, others give you free gas. Still other credit cards offer low interest rates and even insurance for your purchases. Out of all the credit cards that exist, none of them offer the ability to go to a store and make purchases without the actual card. While it is possible to place an order over the phone to a catalog company, it is still generally required to have the card in your hand to read the card number to the sales person and provide some additional information such as the expiration date. Perhaps a trivial number of people have memorized their credit card number and expiration date, but most people have yet to commit these seldom used 20-digits to memory.
Additionally, those with an active lifestyle will find it burdensome to carry many credit cards with them during their everyday lives. The risk of losing one's wallet or purse, or having it stolen is an ongoing problem. The replacement process for most credit cards is long and burdensome. If a credit card is stolen and unauthorized charges are discovered on the account, the process to rectify the situation is both time consuming and exhausting, often involving sworn affidavits by the cardmember.
These and other drawbacks of current credit cards exist.